Method of extracting potash from feldspathic or other potash-bearing rock.



Ufnrr s rarns PATENT orrron.

} ALLERTQN S. CUSHMAN, OF CONNECTICUT; METHOD QF EXTRACTING POTASH FROM FELDSPATHIC OR OTHER POTASH-BEARlNG ROCK.-

To all whom it may concern:

Be it known that I, ALLER'roN S. 'CUSHMAN, a citizen of the United States, and an oflicer of the- Department of Agriculture, and a legal resident-of the State of Connecticut, w ose ost-oifice address is Department of Agricu ture, Washington, District of Columbia, have invented 'new and useful Im rovements in Methodstfor Extracting Potas 1 from F eldspathic or other Potash-Bearing Rock, of which the following is a specification.

This application is made under the act of March 3, 1883, Chapter 143 (22 Stat., 625), and the invention herein described and claimed may be used by the Government of the United States or any of its. ofiicers or employees in the rosecution of work for the United States, or )y any person in the United States, without the payment of any royalty thereon.

This invention has relation to the extraction of potash soda and other soluble bases from ground rocks. Feldspathic or other potash bearing rock is ground to fine powder, slimed with water and placed inside of a wooden cup, box, or other suitable woodencontainer, w lich is then set inside of another larger vessel, which may be made of any suitable material. in the outer vessel and electrodes inserted, so that the inner or slime ci.amber becomes connected with the positive pole, and the outer chamber with the negative pole. A

. current of electricity from a dynamo is then turned on. When this is done the potash, soda and other soluble bases are partially set free from the combinations with alumina and silica in which they exist in thefeldspathic rocks.

Undcr the influence of the passage of the clcctric current (electrolysis) the soluble bases pass through thc wooden partition and the water in the outer vcsscl bocolncs alkaline, owing to the accumulation of poms-- siuin and sodium hydroxid. 'lho electrical resistance of the cells arranged in this way is so high that only a small fraction of an ampcrc passes'thronghiuulcra potential of 110 volts. After a certain crcentage of the alkali has been extracted in this manncr, the

action slows down, and it has bccn found. ncccssary to devise methods to iwcolcratc the act ion.

'l have discovered two methods for accel crating the decomposition of the rock slime and hastening the extraction of the potash:

- Specification-of Letters Patent. Application filed January 14, 1907. Serial R o. 852,187

Water is now placed Pa.tented April 30, 1907.

(a) By a suitable grindin 0r churning ar' rangement the slime in t e inner chamber 'can be kept in a continual agitation, which causes the necessary reactions to go on more rapidly. (b) If a small quantit of l1ydro-' fiuoric acid is added to the slime a very great acceleration in the rate ofdecomposition and extraction is obtained, and it is possible in a reasonably short'time to make a complete extraction of all the potash c0ntained in a feldspathic rock.

If instead of caustic potash it is desired to make various salts of otash such as are in ordinary use for ferti 12ers and other .purposes, a. e., nitrate,'-' sulfate, 'chlorid, and phosphate, the corresponding acids, '5. e., nitric, sulfuric, hydrochloric, and phosphoric, are fed in a dilute form into the outer or so called cathode chamber, fast enough to neutralize the caustic alkali as it forms. By varying the amount of acid added the resistance of the cell can be controlled and'the decomposition of the rock carried on under the best and most economic conditions.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is- 1. A method of extracting potash soda and other alkaline bases, from rocks and minerals containing the alkaline metals, which consists in electrolyzing the material in the anode chamber of a diaphragm cell in an aqueous electrolyte containing hydrolluoric acid.

2. A method for the preparation of the various saltsof potash and other bases asset forth, which consists in electrolyzing the fine ground material in an aqueous electrolyte containing hydrofluoric acid, which is placed in a (-cll in which the anode and'ca'tliode chambers are separated by a diaphragm.

3. A method of extracting potash soda in the cathode chamber by an acid to form a salt.

[ntestimony whereof I ailix my signature in the presence of two subscribed witnesses:

. A. S. (JUSIIMAN.

\Vitnesses:

011$ 11. GATES,

- H. J. Fee-AN. 

